1. Field of the Invention
The present invention relates to a connection device with electrostatic discharge protection, and more particularly, to a connection device capable of avoiding electrostatic discharge to damage related electric devices.
2. Description of the Prior Art
A monitor utilizes a transmission interface to connect with a video signal generating device for receiving and displaying video signals. The specifications of the transmission interface are broadly divided into an analog type such as a video graphics array (VGA) specification, and a digital type such as a digital video interface (DVI) specification, a high-definition multimedia interface (HDMI) specification, and etc. The different interface specifications provide corresponding signal pins (such as a clock signal pin, a data signal pin, a ground signal pin, and etc.) to realize communications and transmissions between the monitor and the video signal generating device.
However, when the video signal generating device starts to communicate with the monitor, if the monitor, under a special operating environment, cannot properly release charges, the monitor may have a very high voltage (such as 90V) due to the accumulated charges caused by the power-up or other reasons. At this moment, the electrostatic charges of the monitor may be discharged to the video signal generating device via a signal pin, such that the video signal generating device is damaged by a large current caused by the high voltage (e.g. 90V). The situation is easier to occur in a factory production line for testing the monitor. Since an operator often requires plugging in the monitor for testing, when the monitor is not connected properly and a ground line is opened, the very expensive test instrument (i.e. the video signal generating device) is easily burned by the large current due to the electrostatic discharge.
In order to solve the burned problem of the test instrument due to the electrostatic discharge, the prior art utilizes an isolation amplifier to sense a voltage drop produced by a external large current flowing through a external resistor and safely outputs a smaller voltage on the other side of the isolation amplifier. However, the prior art can not ensure that the test instrument may not be burned by the smaller voltage. Therefore, the prior art still does not achieve a complete isolation effect to protect against the electrostatic discharge. Thus, there is a need for improvement of the prior art.